Three actors played Clarabell. The first was Bob Keeshan, who later became Captain Kangaroo. Keeshan was succeeded by Robert "Nick" Nicholson,[1] who also played the character of J. Cornelius Cobb on The Howdy Doody Show. Lew Anderson[2] was the third and last person to play Clarabell. Anderson played the character from 1954 until the series' final show on September 24, 1960. Anderson returned to play Clarabell in the short-lived 1976–77 New Howdy Doody Show and in the 1987 40th anniversary special, and in later years in many personal appearances with Buffalo Bob Smith.

Clarabell, who wore a baggy, striped costume, communicated by honking a horn for "yes" or "no". Clarabell would also spray fellow cast member Buffalo Bob Smith with seltzer.

Many attempts were made to find out the real face behind Clarabell. In season 2, #33 of Happy Days, Richie Cunningham is able to get a candid shot of Clarabell (Robert Brunner) without his makeup, but chooses to destroy it after Buffalo Bob tells him to keep the actor's actual face concealed from the public. Based upon the period in which Happy Days is set, Lew Anderson would have been portraying Clarabell during that time.

Who's the funniest clown we know?
Clarabell!
Who's the clown on Howdy's show?
Clarabell!
His feet are big, his tummy's stout,
But we could never do without,
Clara, Clara, Clarabell!

Who has fuzzy-wuzzy hair?
Clarabell!
It's partly red but mostly bare.
Clarabell!
And since the day that he was born,
He's honked and honked and honked his horn.
Clara, Clara, Clarabell!

Clarabell didn't speak until the very end of the final episode. It was only at this moment that Clarabell, still gesturing and using his horn, tells Buffalo Bob that he could actually talk. Amazed, Bob frantically tells Clarabell to prove it as it would be his last chance. The camera slowly moves in close on Clarabell as a drum roll grows louder and then dies out. At this point Clarabell tearfully whispers: "Goodbye, kids."